This is a study of the relation of the renin-angiotensin system and renal and blood vessel prostaglandins to the hemodynamic derangements which occur in patients with cirrhosis and ascites. The study focuses on the capacity of the kidney to balance known vasoconstrictor effects by the production of intrarenal prostaglandins (PGE2), particularly in patients with functional renal failure or the hepatorenal syndrome. The study also addresses the role of blood vessel prostacyclin (PGI2) production in the changes in systemic resistance which often accompany this syndrome.